Hi chickee:
Yep, count me in as having pins and needles on my butt with the pressure on my rectum and feeling of fullness. Annoying is right! That feeling of fullness and pressure on my rectum sometimes translates into messing my pants ever so slightly, which is on the super-annoying scale. The numbing and tingling sensation occurs *just* before the feeling of fullness and pressure.
Part of the reason this is happening for me is because I have a recto-vaginal fistula. My GI said that the feeling of fullness is and the tingling is, in part, the stool wanting to divert through the fistula tract. For sure, when I try to control the rectal pressure to get to the bathroom, I pass stool through my vaginal area rather than through my anus.
I'm not sure what might be causing these symptoms for you, but I'd give the doctor a call to have it checked out.
Stay well,
Kismet